Tension regulating means for winding machines



Dec. 20, 1932. v R. e. JOHNSTONE ET AL 1,891,755 TENSIQN REGULATING MEANS FOR WINDING MACHINES I I Filed Sept. 20. 19:50

ETC r4770 CONTROL CIRCUIT Wren/ans R a Johns/"one A. s. Phi/0; I

Patented Dec. 20, 1932 UNITED STATES PATENT OFFICE RALPH G. JOHNSTON]! AND REGINALD J. S. PHILLIPS, OF MONTREAL, QUEBEC, CANADA, ASSIGNORS TO THE HARLAND ENGINEERING COMPANY OF CANADA LIMITED, 01'

MONTREAL, CANADA TENSION BEGULA'IING MEANS FOR WINDING MACHINES Application filed September 20, 1930. Serial No. 483,218.

This invention relates to improvements in winding machines forpaper and the like and the primary object of the invention is to provide means for maintaining a constant ten- 5 sion on the paper while it is being wound.

At present the usual practice is to pass the paper from the unwinding or supply roll to a rewinding roll lying in the nip of motor driven rewinding rums and to regulate the tension of the sheet by means of a hand operated brake connected to the unwinding roll. The rewinding motor is started slowly and when the paper pulls tight the brake is applied and the motor speeded up. The

manipulation of the brake is left entirely to the operator who gauges the tension of the sheet by observation and adjusts the brake accordingly. Obviously, the tension varies as the unwinding roll decreases in size and fre-' quent adjustment of the brake is necessary. Such a method inevitably causes wide and sudden variations in the tension of the paper during rewinding with resulting defects in the rewound rolls of paper, and fre uently causes breaks in paper during rewin ing.

A uniform and adequately high tension will enable the paper to'be rewound more tightly and uniformly, resulting in fewer breaks. both on the winder and in the print- 0 ing presses, and will produce more compact and smaller rolls for a given weight of paper or, what is more important, a greater amount of aper in a roll of given size.

Xccording to the present invention the usual brake is replaced by a direct current generator directly connected to the unwinding or supply roll and provided with means to maintain the power output of the generator directly proportional to the speed of the paper, whereby the tension of the paper is maintained constant.

In a device of this class, there are two distinct conditions to be dealt with, namely, that prevailing for a short time at the commencement of rewinding when the lineal'speed of the paper is accelerating from zero to the normal operating speed and that prevailin after the operating speed has been attaine characterized by the increasing angular speed of the unwinding roll as its diameter diminishes accompanied by the increasing effectiveness of any constant braking effort.

Assuming the case of rewinding a roll 36 inches in diameter and 150 inches wide wound on a core 8 inches in diameter, the maximum lineal speed of the paper to be 3000 feet per minute and the required tension to be 1 pound per inch of width. The conditions of the foregoing paragraph may be expressed in figures for such a case as follows :-The braking effort required at the lineal speed of 3000 feet per minute is 450,000 pounds er minute or 13.5 H; P. Thus the braking e ort must be capable of increasing in a few minutes from O to 13.5 H. P., the increase being directly proportional to the increase in the linealspeed of the paper. If the rewinding is brought quickly up to full speed, the diameter of the unwinding roll does not diminish appreciably during the acceleration, so that for a lineal speed of 3000 feet per minute the angular speed of the full roll may be taken as 315 R. P. M. As the paper unwinds the angular speed of the roll increases up to 1400 R. P. M. Thus, it will be seen a braking deviceto operate efliciently under the conditions noted must be capable'of rapidly increasing the braking effort from 0 to 13.5 H. P. and capable of thereafter gradually and uniformly diminishing the braking effort at a rate inversely proportional to an angular speed increase from 315 to 1400 R. P. M. or directly proportional to a decrease in roll diameter from 36 inches to 8 inches.

The accompanying drawing illustrates diagrammatically an embodiment of the invention now preferred, but it will be understood the invention is not confined to the embodiment illustrated as modifications and substitutions of equivalents for various elements of the arrangement may be made.

In the drawing Fig. 1 is a diagram illustrating the arrangement of electrical elements and circuits for control of a rewinder driven by a direct current motor.

Fig. 2 is a diagram illustrating the slight modification adapting the invention to a rewinder driven by an alternating current motor.

Referring more particularly to the drawing,11 designates a core on which a roll 12 of paper or other material is wound and 13 designates a pair of winder drums driven in any suitable way by a motor 14. The rewound roll of paper 15 rests in the nip of the drums 13.

According to this invention, a direct current braking generator of suitable design and capacitiy is direct connected to the core of the unwin ing or supply roll. The field 17 of the braking generator is connected in series with a fixed resistance 18 and condenser 19 across an excitation and control circuit 20. A differential vibrating relay 21 is connected in a shunt circuit with the resistance and condenser, one winding 22 of the relay being connected to any suitable means for supplying a reference voltage, for example, a direct current motor 14 driving the winding roll or a direct current generator connected with the winding roll. The other winding 23 of the relay is connected across the generator 16.

The generator is artificially loaded by a rheostat 24 operated by a reversible motor 25 controlled by a current relay 26 in the braking loop, or closed circuit including the generator armature, the rheostat and the relay winding, the pull of the relay winding 27 being opposed by any adjustable means such as a spring 28. As will be seen in the diagram, the motor 25 and its controller 26 are connected in series across the control circuit 20.

For inching when threading paper through the rewinder at starting or if the paper should break during rewinding, a magnetic switch 29 is connected to open up the circuit to the rheostat and winding 27 of the the C. mains. This magnetic switch 29 is controlled by a conveniently located button 30 connected in series with the winding 31 of relay) 3 and place braking generator 16 across.

speed. Thus, if the current is ke t constant during this period, a condition is obtained whereby the output of the generator varies with the lineal speed of the paper. The m0- tor operated rheostat and current relay 26 function to maintain the current constant at a predetermined figure. With no current flowing in the circuit, the relay 26 cuts the rheostat all out, so that when starting up the generator is virtually short-circuited.

\Vhen the winder has been brought up to speed, the differential vibrating relay 21 operating in conjunction with the fixed resistance 18 and condenser 19 in the generator field serves to keep the voltage of the brakinggenerator relatively the same as that of the direct current motor 14 or of any other voltage reference means. The operation of the relay 21 is to cut the resistor 18 alternately into and out of circuit, and the frequency of vibration determines the mean field value. During the acceleration period, the relay 21 will. for the most part, remain closed since the two voltages are approximately the same. As the paper continues to unwind at constant lineal speed, the diameter of the roll diminishes and the angular speed of the supply roll consequently increases. The generator speed increases correspondingly and the voltage tends to go up but the differential relay 21 operates to maintain it at the value corresponding to that on the reference voltage element. Thus, since the voltage and current are kept constant irrespective of change in the diameter of the unwinding roll, the output of the braking generator remains constant and the generator exerts a braking effort which varies directly with the lineal speed of the paper and thus the tension of the paper is kept constant.

If the winder is driven by an alternatin current motor, the generator 32 furnishes ref erence voltage for the relay 21 in exactly the same way as does the direct current motor 14 and the device operates exactly as described, substituting the pilot generator 32 for the motor.

In the following claims, the term reference voltage means or equivalent term, is to be understood as including either a direct current motor driving the rewinder or a direct current generator directly driven by the re winder or its motor.

Having thus described our invention, what we claim is 1. Tension regulating means for winding machines comprising the combination with a supply roll and a winding roll, of a direct current generator direct connected to the supply roll, a direct current generator connected with the winding roll to furnish reference voltage directly proportional to the lineal speed of the material being wound, and means to apply the reference voltage against the generator voltage to maintain the voltage and output of the generator constantly propora supply roll and a winding roll, of a direct tion l to the reference Voltage. current generator direct connected to the 2. Tension regulating means for winding su ply roll, means to maintain the generator machines comprising the combination with a v tage proportional to the lineal speed of 5 supply roll and a winding roll, of a direct the material, and meansto load the generator 70 current generator direct connected to the supproportionally to the speed thereof whereby ply roll, a variable resistance normally in ciruniform tension is maintained in the material cuit with the armature of said generator, being wound. means responsive to variations in generator In Wltness whereof, we have hereunto set speed to vary said variable resistance direct- 111 h n 76 ly as the generator speed, means connected LPH G- JOHNSTONE. with the winding roll to furnish reference REGINALD J. S. PHILLIPS.

voltage directly proportional to the lineal speed of the material being wound, and means to apply the reference voltage against the gen- 80 erator voltage to vary the field value of the generator.

3. Tension regulating means for winding machines comprising the combination with a ifisupply roll and a winding roll, of a direct curv rent generator direct connected to the supply roll, a variable resistance normally in circuit with the armature of said generator, means responsive to variations in generator speed 25 to vary said variable resistance directly as the generator speed, a fixed resistance in the field of said generator, means connected with the winding roll to furnish reference voltage directly proportional to the lineal speed of the material being wound, and means responsive 96 to relative variations between said reference voltage and the generator voltage to out said fixed resistance into and out of the generator field thereby to regulate the voltage of the generator.

4. Tension regulating means for winding machines comprising the combination with a supply roll and a winding roll, of a direct current generator direct connected to the supply roll, a motor operated variable resistance 106 normally in circuit with the armature of said generator and a current relay controlling the actuating motor of said variable resistance. the actuating winding of said relay being in circuit with the generator armature, adjust-' 110 I able means opposing the pull of the winding, a fixed resistance in circuit with the field of said generator and a differential current vibrating relay having one of its actuating 0 windings in circuit with said reference volt age means and the other of its actuating windings in circuit with the generator armature, said relay being arranged to cut the fixed resistance alternately into and out of gen- 5 erator field. 7

5. Tension regulating means according to claim 4, in which the reference voltage furnishing means is a directdurrent motor drivmg the winding roll. 6. Tension regulating means according to claim 4, in which the reference voltage furnishing means is a direct current generator connected with the winding roll.

7. Tension regulatin means for windin machines comprising. tie combination wit 

